Aperture
size of a transducer element (for a single-element transducer) or group of elements (for an array)
Apodization
nonuniform (i.e involving different voltage amplitudes) driving of elements to an array to reduce grating lobes
Array
a transducer assembly containing several piezoelectric elements
Axial
in the direction of the transducer axis (sound travel direction)
Axial Resolution
the minimum reflector separation along the sound path that is required to produce separate echoes (i.e to distinguish between two reflectors)
Beam
region containing continuous wave sound; region through which a sound pulse propagates
Composite
combination of piezoelectric ceramic and a nonpiezoelectric polymer
Convex array
curved linear array
Crystal
element
Curie Point
temperature at which an element material loses its piezoelectric properties
Damping
material attached to the rear face of transducer element to reduce pulse duration; the process of pulse duration reduction
Detail resolution
the ability to image fine detail and to distinguish closely spaced reflectors.
Disk
a thin, flat, circular object
Dynamic aperture
aperture that increases with increasing focal length (to maintain constant focal width)
Dynamic focusing
continuously variable reception focusing that follows the increasing depth of the transmitted pulse as it travels
Element
the piezoelectric component of transducer assembly
Elevational resolution
the detail resolution in the direction perpendicular to the scan plane. it its equal to the section thickness and is the source of section thickness artifact
far zone
the region of a sound beam in which the beam diameter increases as the distance from the transducer increases; also called far field
focal length
distance from a focused transducer to the center of a focal region or to the location of the spatial peak intensity.
focal region
region of minimum beam diameter and area
focal zone
length of the focal region
focus
the concentration of the sound beam into a smaller beam area that would exist otherwise
grating lobes
additional weaker beams of sound traveling out in directions different from the primary beam as a result of the multi-element structure of transducer arrays
lateral
perpendicular to the direction of sound travel
lateral resolution
minimum reflector separation perpendicular to the sound path that is required to produce separate echoes
lead zirconate titanate
a ceramic piezoelectric material. abb PZT.
lens
a curved material that focuses a sound or light beam
linear
adjectival form of line
linear array
array made of rectangular elements arranged in straight line
linear phased array
linear array operated by applying voltage pulses to all elements, but with small time differences (phasing) to direct ultrasound pulses out in various directions
linear sequenced array
linear array operated by applying voltage pulses to groups of elements sequentially.
matching layer
material attached to the front face of a transducer element to reduce the reflections at the transducer surface
natural focus
the narrowing of a sound beam that occurs with an unfocused flat transducer element
near zone
the region of sound beam in which the beam diameter decreases as the distance form the transducer increases; also called near field
operating frequency
preferred (max efficiency) frequency of operation of a transducer
phased array
an array that steers and focuses the beam electronically (with short time delays)
phased linear array
linear sequenced array with phased focusing added linear sequenced array with phased steering of pulses to produce a parallelogram- shaped display
piezoelectricity
conversion of pressure to electric voltage
probe
transducer assembly
resolution
the ability to distinguish echoes in terms of space, time, or strength (called detail, temporal, and contrast resolutions)
resonance frequency
operating frequency
scanhead
transducer assembly
sector
a geometric figure bounded by two radii and the arc of the circle included between them
sensitivity
ability of an imaging system to detect weak echoes
side lobes
weaker beams of sound traveling out from a single element in direction different form those of a primary beam
sound beam
the region of a medium that contains virtually all of the sound produced by a transducer
source
an emitter of ultrasound; transducer
transducer
a device that converts energy from one form to another
transducer assembly
transducer element with damping and matching material assembled in a case
ultrasound transducer
a device that converts electric energy to ultrasound energy; and vice versa
vector array
linear sequenced array that emits pulses from different starting points and (by phasing) in different directions.
